The present invention relates to an automatic design processing system for creating machining design processes for parts.
There is a paper by Iwata et al. entitled "Automation of Production Design", in The Journal of the Information Processing Society of Japan, Vol. 124, No.1, 1983, pp. 32-40, which discloses a conventional automatic processing system for process design in machining parts. FIG. 1 is a block diagram illustrating a flow of information in a production design of machine parts, which is employed in the above-mentioned conventional automatic processing system. A system based on the conventional system will be described hereunder.
In FIG. 1, reference numeral 1 designates a conversation type process design processing section for deciding process information for machining a product (or parts) through the selection or input by a production designer. The process design processing section 1 is constituted by the following elements 1-1 to 1-4. The element 1-1 is a processing section for extracting a designated area to be machined and the parts and machining processes therefor, the element 1-2 is a processing section for deciding the order of the extracted machining processes, the element 1-3 is a processing section for selecting machining devices for performing the assigned machining processes and deciding the order of use of the selected machining device, and the element 1-4 is a processing section for deciding a design of a fixture or holder required for fixing the attitude of a (intermediate) blank decided for every process and for deciding conditions (working instructions) in the fixing operation.
In FIG. 1, reference numeral 2 designates a working design processing section for automatically processing a working plan for specific operations of the machining process on the basis of the result of a process plan of the above-mentioned process design processing section I. The working design processing section 2 is constituted by elements 2-1 to 2-4 as follows. The element 2-1 is a processing section for deciding specific machining operations and the order thereof for the machining processes allocated to every process, the element 2-2 is a processing section for selecting a tool to be used in every machining operation, the element 2-3 is a processing section for deciding machining conditions such as a cutting speed, a feeding speed, a cutting depth and so on in every machining operation, and the element 2-4 is a processing section for obtaining a desired path of a tool in every machining operation, and for producing an NC tape for realizing the machining.
In FIG. 1, the reference number 3 designates a data base to be referenced in automatically deciding and supporting a machining operation, in which a machine file, a tool file, a working development file, a material file and so on are prepared. In FIG. 1, reference numeral 4 designates a display portion for graphically displaying the shape of parts or a blank, and for displaying a menu provided for allowing an operator to execute input or selection choices found on the menu, for example.
Next, the operation of the system having the above-mentioned configuration will be described. Information about parts to be machined is inputted, for example, in the form of an image of a parts drawing from a higher ranking computer-aided design (CAD) system and the thus inputted information is displayed by the display portion 4. The information in the drawing includes the shape and precision or accuracy (surface roughness, size tolerance, degree of perpendicularity, and so on) required by the parts, and so on. Although this raw information can be understood by a production designer, a computer cannot understand the meaning of the raw information and regards the raw information merely as points, lines and characters. In the step of the process design 1, the production designer himself extracts areas to be machined and machining processes from the displayed parts information on the basis of his experience (1-1).
In the decision 1-2 of machining processes, the allocation of machining tools thereto, the order of the machining processes, and areas to be machined are indicated by hitting the corresponding portions of the shape of the parts displayed on the graphic display, and machining processes of the areas to be machined are selected from a menu having a turning process, a milling process, a drilling process, or the like, so that the machining processes and the order thereof are inputted. The machining devices or tools to be used in the respective machining processes are inputted by selecting the numbers in a number menu of the machining devices 1-3. Next, roughly considering the attitude or spatial disposition of a blank, the areas to be machined and tool paths for every process, the kind and disposition of a fixture in the process is decided (1-4).
The step of the working design 2 is performed somewhat automatically as follows. A plurality of workings or operations required for an area to be machined are decided by use of a working know-how file, for example, (201). The working know-how file is searched on the basis of the name of the area to be machined and accuracy information, for example, to develop a desired working operation. The "working know-how" means the development of a specific working or machining operation, such as "rough machining .fwdarw. intermediate finish machining .fwdarw. finish machining .fwdarw. chamfering" in a boring machining, "center hole drilling .fwdarw. drilling .fwdarw. chamfering .fwdarw. tapping" in a tap machining, and so on.
Next, tools and machining conditions are decided with reference to a "data base file" which is provided in advance as know-how for machining. Preferred tools are selected by searching a "tool file" in view of the points of a machine, a machining method, shape data, accuracy data, and so on (2-2). Machining conditions such as cutting speed, feeding speed and so on are decided by searching a "material file", a "machine file" and so on in view of the points of characteristics of a machining method, a material and a tool (2-3).
Finally, a numerical control (NC) tape for controlling a tool path is produced by referring to a shape, a tool, a machining operation and so on for every operation (2-4). This tool path is indicated on a graphic display, so that an operator can check the appropriateness thereof.
If a problem occurs in the check of the tool path or in any other step, the operator goes back to the preceding step to perform the processing again.
In the conventional process design processing system as has been described, working designs other than a simple one are decided depending on the experience and know-how of a production designer. Accordingly, if the production designer makes a wrong judgement in a processing step, a problem occurs in that a fixing or working plan succeeding the processing step is in vain.
Although a process plan is decided based on the characteristics of machining devices or fixtures, the machining accuracy of parts being machined in the operations, and machining know-how, the decision has not been automated in the conventional system. Although data bases such as a working development file are structured to automate a working design, the automation has been limited to simple drilling and processing other than a tolerance processing, and the automation level has been too low to make a computer perform the entire tolerance processing and so on. On the other hand, since it becomes possible to perform several processes of a conventional machine tool by a single operation by using a combined machine tool such as a horizontal machining center or a turning center, high-accuracy and high-efficiency machining are achievable. However, a process design for a combined machine tool having a high degree of freedom is very difficult, and there has been another problem that a conventional process design processing system which depends on the experience or know-how of a production designer in deciding a process design other than a simple one cannot cope with such a difficult process design.